Cancer is a group of more than 100 diseases caused by the
uncontrolled growth and spread of abnormal cells. Tumors, or
abnormal growth of tissue, may be benign or malignant. Benign
tumors are usually slow-growing and not life-threatening, whereas
malignant tumors (or cancers) are made up of cells with abnormal
genetic material (or DNA) and grow more rapidly. Malignant
tumors have a tendency to invade neighboring tissues or organs
and to travel and grow in other areas of the body (i.e. to
metastasize). If the spread of the cancer is not stopped,
cancer cells invade vital organs which can result in death.
Cancer cells may remain at their original site (local stage),
spread to an adjacent area of the body (regional stage), or
spread throughout the body (distant stage). Cancers at the
local, regional or distant stage are considered invasive. A very
early cancer found in only a few layers of cells, called in situ
cancer, is considered non-invasive. (Please see the Glossary for
definitions of many of these terms.)

What Causes Cancer

Cancers are thought to be caused by a variety of factors working
alone or in combination. Some cancers are caused by external
factors such as tobacco, diet, certain chemicals, radiation, and
viruses and some by internal factors such as hormones, immune
conditions, and inherited genetic mutations. Usually ten or more
years pass between exposure to a factor that causes cancer and
the detectable disease.

Cancer Incidence and Mortality in the U.S.

Cancer is the second leading cause of death in the U.S., with
1,228,600 new cases and 564,800 deaths estimated for 1998. Over
the past 50 years, the death rate from cancer has increased due
mainly to a large rise in lung cancer death rates resulting from
smoking. During the past few years cancer rates have begun to
decrease, possibly as a result of healthier lifestyles,
particularly decreases in smoking. Cancer occurs in people of
all ages, but its occurrence increases greatly in people over 45
years of age. However, it is also the leading cause of
non-accidental death among U.S. children under 15. Men have a higher
mortality rate due to cancer than women, and blacks have the
highest cancer mortality rate of any major racial group. In the
U.S., men have about a 1 in 2 lifetime risk of developing cancer
and women have about a 1 in 3 lifetime risk. A much higher
percentage of people diagnosed with cancer now are surviving
than people diagnosed with cancer in earlier years. Now, about
four of every ten people diagnosed with cancer will survive for
at least five years.

General Information on Breast Cancer1-6

Incidence in the U.S.

Breast cancer is the most common type of cancer among women in
the U.S., accounting for 30 percent of the newly diagnosed cases
of cancer among women each year. About 178,700 new cases are
estimated for 1998 in the U.S. Approximately one in eight women
in the U.S. will have breast cancer at some time in her life,
according to the American Cancer Society. The age-adjusted
incidence rate of breast cancer among women in the U.S. steadily
increased between 1940 and 1987, especially between 1982 and
1987, but has stabilized since 1987 at about 110 newly diagnosed
cases per 100,000 women a year. Many researchers believe that
some of the increase in breast cancer incidence since 1940 may
be due to an increase in the proportion of women who have known
risk factors for breast cancer, such as giving birth to the first
child later in life and having fewer children. Another possible
reason for the increase in the incidence of breast cancer,
especially from 1982 to1987, is that more women are using breast
cancer screening methods such as mammography that identify breast
cancer early. Thus, breast cancers that would have been
diagnosed in later years (after 1982-1987) were diagnosed
earlier. Breast cancer is rare among men; about 1,600 new cases
of breast cancer in men are estimated to occur in 1998 in the
U.S., representing 0.25 percent of the total estimated cancers
in men.

Mortality in the U.S.

Breast cancer is the second most common cause of death due to
cancer in women in the U.S. (lung cancer has recently become the
most common) with 43,500 deaths estimated nationwide for 1998.
The mortality rate of breast cancer among women is declining.
The reasons for the decline are believed to include earlier
detection which enables more successful treatment. The five-year
relative survival rate for localized breast cancer is 97 percent,
for regionally spread breast cancer it is 76 percent, and for
women with distant metastases it is 21 percent.

Risk Factors for Breast Cancer Among Women

Many risk factors for breast cancer are known.

Age - The risk of breast cancer increases sharply after age 30. This is the single
most important risk factor.

Socio-economic status - The risk of breast cancer is higher among women of higher
socio-economic status. This appears to be explained largely by the reproductive
risk factors.

Family history - The risk of breast cancer is increased
when close relatives have had breast cancer, particularly
a first degree relative such as a mother or sister. The risk is
even higher if the first degree relative with breast cancer was
premenopausal and had bilateral breast cancer (breast
cancer in both breasts). Some breast cancers with a
family history may be the result of a specific inherited gene (or
genetic trait). Within the past few years two breast cancer
genes have been discovered, BRCA-1 and BRCA- 2;
mutation of either of these genes is believed to greatly
increase susceptibility to breast cancer. Other breast
cancers with a family history may be because of lifestyle
similarities or the inheritance of certain other risk factors
such as menstrual patterns and obesity.

Personal medical history - Women who have had cancer in
one breast have a higher risk of developing a second
cancer. Women with ovarian or endometrial cancer also
are at higher risk for breast cancer.

Benign breast disease - Women with benign fibrocystic
breast disease confirmed by biopsy are at higher risk of
breast cancer. Several studies suggest that the increased
risk associated with benign breast disease may be mostly among
women with atypical hyperplasia (an abnormal increase in
the number of cells in a specific area such as the lining
of the breast ducts).

Menstrual history - Early age at the onset of
menstruation and late age at menopause are risk factors for
breast cancer. Menopause induced by the removal of the ovaries
before age 40 reduces the risk of breast cancer.

Reproductive history - Never having children or having
the first live birth at a late age are associated with an
increased risk of breast cancer.

Ionizing radiation - Large doses of radiation have been
associated with breast cancer in women exposed to atomic
bomb fallout at Hiroshima and Nagasaki. Women who were
exposed to large doses of x-rays as part of the treatment for
tuberculosis from 1935 to 1954 had a high incidence of
breast cancer. The much lower doses of radiation
used today for chest x-rays or mammograms are considered to be of
little or no risk. (The benefits of mammography at
intervals recommended by the American Cancer Society far
outweigh any risk.)

Alcohol use - Recent studies have found an increase in
breast cancer risk among women who have three or more
alcoholic drinks a day, compared to non-drinkers.

Dietary factors - A few studies found a small increase
in breast cancer risk among women with high fat diets.
However, more recent large studies have not found an
association between fat intake and breast cancer.5

Use of hormones - Long-term exposure to postmenopausal
estrogen replacement therapy may increase
the risk of breast cancer. Most studies have not found an
association between oral contraceptive use and breast
cancer. However, some recent studies suggest a possible
increase in breast cancer before age 45 among women who
used oral contraceptives for a long time or who started oral
contraceptive use at an early age.5

The above risk factors partly explain the cases of breast cancer
among women.6 Pesticides and other chemicals which mimic or
modify the action of estrogens are currently under study by
various research institutions. Also under study are a diet high
in fat, physical inactivity, hormone replacement therapy, genetic
factors, and gene-environmental interactions.

Risk Factors for Breast Cancer in Men

The causes of male breast cancer are not as well understood.
Some factors thought to increase the risk of male breast cancer
are excess weight in young adulthood, gynecomastia (abnormal
swelling of the breasts), Klinefelter=s syndrome (an extra X
chromosome), and undescended testes; all possibly related to
higher levels of estrogen. Men with a family history of breast
cancer, especially a female relative who developed breast cancer
before age 45, are at higher risk of breast cancer. High doses
of ionizing radiation also can cause male breast cancer. It is
thought that the lower estrogen levels in men compared to women
may partially explain the much lower rate of breast cancer in
men compared to women.

Prevention

Given the known risk factors for breast cancer, opportunities for
prevention are limited. The following should be studied further
to see if they reduce the risk of breast cancer: moderate
physical activity, a diet low in fat and high in fiber, weight
control (particularly in women after menopause), and limited
consumption of alcoholic beverages. A study of the use of
tamoxifen, a drug that is prescribed for women who have had
breast cancer to prevent recurrence, indicates that tamoxifen may
prevent breast cancer in high risk women. However, there is
concern that tamoxifen may have serious short- and long-term side
effects. Other medications which may have similar benefits but
are less hazardous are under study.

For now, early detection and treatment are the best means to
increase survival and reduce mortality due to breast cancer.
Mammography, breast examination by a nurse or physician, and
breast self-examination, are all methods to detect breast cancer
early. Mammography is especially important because it can detect
early breast cancers that even very skilled health practitioners
may miss. Appendix I contains recommendations from the American
Cancer Society for women about using these methods of early
detection. Appendix II has information on the New Jersey Breast
and Cervical Cancer Control Initiative which provides for free
screening of eligible women in New Jersey.

Additional Information

For additional free information on breast and other cancers these
organizations may be contacted:

Office of Cancer Epidemiology, New Jersey Department of
Health and Senior Services - phone 609-588-3500 or access
the Internet at www.state.nj.us/health.
The Office of Cancer Epidemiology has incidence data on cancer in New Jersey
from the New Jersey State Cancer Registry and
informational materials from a variety of organizations.

New Jersey Breast and Cervical Cancer Control Initiative
(NJBCCCI), New Jersey Department of Health and Senior
Services - phone 609-292-8540. The NJBCCCI provides for free
breast and cervical cancer screening for eligible women and has
informational materials such as an outreach video, "The Faces and
Voices of Hope," a brochure, "Early Detection is Your
Best Protection," and a resource directory (see Appendix II
for more information).

American Cancer Society - phone 1-800-ACS-2345 (or 1-800-227-2345)
or access the Internet at www.cancer.org. The
American Cancer Society is a nationwide, community-based,
voluntary health organization dedicated to eliminating
cancer as a major health problem by preventing cancer,
saving lives and diminishing suffering from cancer, through
research, education, advocacy, and service.

National Cancer Institute - phone 1-800-4-CANCER
(or 1-800-422-6237) or access the Internet at www.nci.nih.gov.
The Cancer Information Service (CIS) of the National
Cancer Institute provides a nationwide telephone service for the
public, cancer patients and their families. Their health
care professionals can answer questions in English and
Spanish and send printed materials. People with TTY equipment
for the hearing-impaired may call 1-800-332-8615.